Case studies of equivalent fuzzy subgroups of finite abelian groups
- Authors: Ngcibi, Sakhile L
- Date: 2002
- Subjects: Abelian groups , Fuzzy sets
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5401 , http://hdl.handle.net/10962/d1005215 , Abelian groups , Fuzzy sets
- Description: The broad goal is to classify all fuzzy subgroups of a given type of finite group. P.S. Das introduced the ntion of level subgroups to characterize fuzzy subgroups of finite grouops. The notion of equivalence of fuzzy subgroups which is used in this thesis was first introduced by Murali and Makamba. We use this equivalence to charterise fuzzy subgroups of inite Abelian groups (p-groups in particular) for a specified prime p. We characterize some crisp subgroups of p-groups and investigate some cases on equi valent fuzzy subgroups.
- Full Text:
- Date Issued: 2002
- Authors: Ngcibi, Sakhile L
- Date: 2002
- Subjects: Abelian groups , Fuzzy sets
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5401 , http://hdl.handle.net/10962/d1005215 , Abelian groups , Fuzzy sets
- Description: The broad goal is to classify all fuzzy subgroups of a given type of finite group. P.S. Das introduced the ntion of level subgroups to characterize fuzzy subgroups of finite grouops. The notion of equivalence of fuzzy subgroups which is used in this thesis was first introduced by Murali and Makamba. We use this equivalence to charterise fuzzy subgroups of inite Abelian groups (p-groups in particular) for a specified prime p. We characterize some crisp subgroups of p-groups and investigate some cases on equi valent fuzzy subgroups.
- Full Text:
- Date Issued: 2002
Catalytic behaviour of metallophthalocyanines towards the detection of nitric oxide
- Authors: Vilakazi, Lea Sibulelo
- Date: 2002
- Subjects: Electrochemistry Nitric oxide
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4418 , http://hdl.handle.net/10962/d1006852
- Description: Electrocatalytic reduction and oxidation of nitric oxide (NO) using cobalt phthalocyanine complexes have been studied and compared to vitamin B₁₂ and other metallophthalocyanine (MPc) complexes. Modifying a glassy carbon electrode with these complexes resulted in improved sensitivity of the electrode allowing detection of NO to 10⁻⁹ mol dm⁻³. The mechanisms of catalysis were studied. Electrocatalysis of NO involves coordination of NO to the MPc complex. Hence catalytic activity is affected by the nature of the metal center. However coordination of NO to the MPc complex has to be reversible to eliminate poisoning of the electrode. Though FePc gave the best sensitivity and lowered the reduction potential more than CoPc, the strong Fe-NO bond resulted in the poisoning of the electrode hence, rendering the electrode unstable. Rate constants for NO coordination to the MPc complexes were studied. These rates were smaller than the studied NO porphyrin coordination rates. Electrocatalytic reduction of NO using MPc complexes involves a transfer of an electron from the metal center to the NO ligand. Hence, substitution of electron-donating grohps on the cobalt pthalocyanine complex resulted in improved sensitivity and catalytic activity. A CoPc modified microelectrode (11μm) was used to monitor NO in human blood components and to detect NO in a rat brain. Detections of NO were also done in aqueous solutions in the presence of interfering species such as dopamine and serotonin. An interaction between NO and serotonin was observed.
- Full Text:
- Date Issued: 2002
- Authors: Vilakazi, Lea Sibulelo
- Date: 2002
- Subjects: Electrochemistry Nitric oxide
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4418 , http://hdl.handle.net/10962/d1006852
- Description: Electrocatalytic reduction and oxidation of nitric oxide (NO) using cobalt phthalocyanine complexes have been studied and compared to vitamin B₁₂ and other metallophthalocyanine (MPc) complexes. Modifying a glassy carbon electrode with these complexes resulted in improved sensitivity of the electrode allowing detection of NO to 10⁻⁹ mol dm⁻³. The mechanisms of catalysis were studied. Electrocatalysis of NO involves coordination of NO to the MPc complex. Hence catalytic activity is affected by the nature of the metal center. However coordination of NO to the MPc complex has to be reversible to eliminate poisoning of the electrode. Though FePc gave the best sensitivity and lowered the reduction potential more than CoPc, the strong Fe-NO bond resulted in the poisoning of the electrode hence, rendering the electrode unstable. Rate constants for NO coordination to the MPc complexes were studied. These rates were smaller than the studied NO porphyrin coordination rates. Electrocatalytic reduction of NO using MPc complexes involves a transfer of an electron from the metal center to the NO ligand. Hence, substitution of electron-donating grohps on the cobalt pthalocyanine complex resulted in improved sensitivity and catalytic activity. A CoPc modified microelectrode (11μm) was used to monitor NO in human blood components and to detect NO in a rat brain. Detections of NO were also done in aqueous solutions in the presence of interfering species such as dopamine and serotonin. An interaction between NO and serotonin was observed.
- Full Text:
- Date Issued: 2002
Chemical studies of selected chromone derivatives
- Authors: Nchinda, Aloysius Tchangwe
- Date: 2002
- Subjects: Heterocyclic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4434 , http://hdl.handle.net/10962/d1007442
- Description: This investigation has been geared towards several aspects of chromone chemistry. Selected 2-(N,N-dimethylarnino)chromones have been synthesized via 2-hydroxyacetophenone boron difluoride complex intermediates, and potentiometric analysis of these compounds in ethanolwater has been used to determine the influence of substituents on their basicity. The pKa values have been found to lie within a narrow range (1.92 - 2.52), and the observed substituent effects have been rationalized with the aid of semi-empirical and ab initio molecular orbital calculations. An efficient route has been developed for the synthesis of the naturally-occurring chromone, "granulosin" [7,8-(methylenedioxy)-2-propylchromone], and several C-2 side chain analogues in good yields, by condensing 2'-hydroxy-3',4'-(methylenedioxy)acetophenone with a range of ethyl carboxylate esters. These compounds show significant cytotoxic activity against the brine shrimp, Artemia salina, and two of them, the 2-ethyl and 2-benzyl derivatives also show 100% activity as pesticides on Beet army worms (BAW). Another naturally-occurring chromone derivative, 5-hydroxy-2-isopropyl-7-methoxychromone, and four C-2 side chain analogues have been prepared in moderate yields. These compounds also show significant cytotoxic activity against the brine shrimp, Artemia salina, and it is apparent that the presence of the hydroxyl group at C-5 is critical for such activity. The electronimpact mass spectra of both series of chromone derivatives have been investigated, permitting the elucidation of characteristic fragmentation patterns. In work directed towards the synthesis of potential HIV -1 protease inhibitors, five novel chromone-containing analogues of the clinically useful drug, ritonavir, have been synthesized. The design strategy has involved the coupling of substituted chromone-2- carboxylic acids with a specially prepared, hydroxyethylene dipeptide isostere to afford ritonavir analogues containing chromone termini. An interactive docking procedure has been used to explore the docking of ritonavir and the novel chromone-containing analogues into ' the active site of the enzyme, and has indicated the capacity of the ritonavir analogues to form hydrogen-bonds with the HJV-l enzyme receptor. Various substituted cbromone-3-carbaldehydes, which have been synthesized from the corresponding o-hyclroxyacetophenones using Vilsmeier-Haack methodology, have been examined as substrates for Morita-Baylis-Hillman reactions, using 3-hyclroxyquinuclidine as the catalyst and arcylonitrile and methyl acrylate as the activated alkenes. Optimization of the reaction conditions has permitted efficient conversion of the cbromone-3-carbaldehydes to the Morita-Baylis-Hillman products and, in some cases, dimeric products, within 24 h. Heating of the Morita-Baylis-Hillman products, arising from reactions with methyl acrylate, at 80 ºC for 3 h in the presence of DABCO as catalyst, has been shown to effect transformation to the corresponding dimers in good yield.
- Full Text:
- Date Issued: 2002
- Authors: Nchinda, Aloysius Tchangwe
- Date: 2002
- Subjects: Heterocyclic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4434 , http://hdl.handle.net/10962/d1007442
- Description: This investigation has been geared towards several aspects of chromone chemistry. Selected 2-(N,N-dimethylarnino)chromones have been synthesized via 2-hydroxyacetophenone boron difluoride complex intermediates, and potentiometric analysis of these compounds in ethanolwater has been used to determine the influence of substituents on their basicity. The pKa values have been found to lie within a narrow range (1.92 - 2.52), and the observed substituent effects have been rationalized with the aid of semi-empirical and ab initio molecular orbital calculations. An efficient route has been developed for the synthesis of the naturally-occurring chromone, "granulosin" [7,8-(methylenedioxy)-2-propylchromone], and several C-2 side chain analogues in good yields, by condensing 2'-hydroxy-3',4'-(methylenedioxy)acetophenone with a range of ethyl carboxylate esters. These compounds show significant cytotoxic activity against the brine shrimp, Artemia salina, and two of them, the 2-ethyl and 2-benzyl derivatives also show 100% activity as pesticides on Beet army worms (BAW). Another naturally-occurring chromone derivative, 5-hydroxy-2-isopropyl-7-methoxychromone, and four C-2 side chain analogues have been prepared in moderate yields. These compounds also show significant cytotoxic activity against the brine shrimp, Artemia salina, and it is apparent that the presence of the hydroxyl group at C-5 is critical for such activity. The electronimpact mass spectra of both series of chromone derivatives have been investigated, permitting the elucidation of characteristic fragmentation patterns. In work directed towards the synthesis of potential HIV -1 protease inhibitors, five novel chromone-containing analogues of the clinically useful drug, ritonavir, have been synthesized. The design strategy has involved the coupling of substituted chromone-2- carboxylic acids with a specially prepared, hydroxyethylene dipeptide isostere to afford ritonavir analogues containing chromone termini. An interactive docking procedure has been used to explore the docking of ritonavir and the novel chromone-containing analogues into ' the active site of the enzyme, and has indicated the capacity of the ritonavir analogues to form hydrogen-bonds with the HJV-l enzyme receptor. Various substituted cbromone-3-carbaldehydes, which have been synthesized from the corresponding o-hyclroxyacetophenones using Vilsmeier-Haack methodology, have been examined as substrates for Morita-Baylis-Hillman reactions, using 3-hyclroxyquinuclidine as the catalyst and arcylonitrile and methyl acrylate as the activated alkenes. Optimization of the reaction conditions has permitted efficient conversion of the cbromone-3-carbaldehydes to the Morita-Baylis-Hillman products and, in some cases, dimeric products, within 24 h. Heating of the Morita-Baylis-Hillman products, arising from reactions with methyl acrylate, at 80 ºC for 3 h in the presence of DABCO as catalyst, has been shown to effect transformation to the corresponding dimers in good yield.
- Full Text:
- Date Issued: 2002
Continuity and generalized continuity in dynamics and other applications
- Authors: Mimna, Roy Allan
- Date: 2002
- Subjects: Topological dynamics -- Research Dynamics -- Mathematical models -- Research Perturbation (Mathematics) Attractors (Mathematics) Baire classes Mathematics -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5404 , http://hdl.handle.net/10962/d1005218
- Description: The topological dynamics of continuous and noncontinuous dynamical systems are investigated. Various definitions of chaos are studied, as well as notions of stability. Results are obtained on asymptotically stable sets and the perturbation stability of such sets. The primary focus is on the traditional point sets of topological dynamics, including the chain recurrent set, omega-limit sets and attractors. The basic setting is that of a continuous function on a compact metric space, sometimes with additional properties on the space. The investigation includes results on the dynamical properties of typical continuous functions in the sense of Baire category. Results are also developed concerning dynamical systems involving quasi-continuous functions. An invariance property for the omega-limit sets of such functions is given. Omega-limit sets are characterized for Riemann integrable derivatives and derivatiyes which are continuous almost everywhere. Techniques used in the investigation and formulation of results include finding theorems which relate the rather disparate notions of dynamical properties and generalized continuity. In addition to dynamical systems, numerous other applications of generalized continuity are imoestigated. Techniques used include application of the Baire Category Theorem and the notion of semi-closure. For example, results are formulated concerning functions determined by dense sets, including separately continuous functions, thus generalizing the classical result for continuous functions on dense subsets of the domain. The uniform boundedness theorem is extended to functions which are not necessarily continuous, including various derivatives. The closed graph theorem is strictly generalized in two separate ways, and applications are presented using these generalizations. An invariance property of separately continuous functions is given. Cluster sets are studied in connection with separate continuity, and various results are presented concerning locally bounded functions.
- Full Text:
- Date Issued: 2002
- Authors: Mimna, Roy Allan
- Date: 2002
- Subjects: Topological dynamics -- Research Dynamics -- Mathematical models -- Research Perturbation (Mathematics) Attractors (Mathematics) Baire classes Mathematics -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5404 , http://hdl.handle.net/10962/d1005218
- Description: The topological dynamics of continuous and noncontinuous dynamical systems are investigated. Various definitions of chaos are studied, as well as notions of stability. Results are obtained on asymptotically stable sets and the perturbation stability of such sets. The primary focus is on the traditional point sets of topological dynamics, including the chain recurrent set, omega-limit sets and attractors. The basic setting is that of a continuous function on a compact metric space, sometimes with additional properties on the space. The investigation includes results on the dynamical properties of typical continuous functions in the sense of Baire category. Results are also developed concerning dynamical systems involving quasi-continuous functions. An invariance property for the omega-limit sets of such functions is given. Omega-limit sets are characterized for Riemann integrable derivatives and derivatiyes which are continuous almost everywhere. Techniques used in the investigation and formulation of results include finding theorems which relate the rather disparate notions of dynamical properties and generalized continuity. In addition to dynamical systems, numerous other applications of generalized continuity are imoestigated. Techniques used include application of the Baire Category Theorem and the notion of semi-closure. For example, results are formulated concerning functions determined by dense sets, including separately continuous functions, thus generalizing the classical result for continuous functions on dense subsets of the domain. The uniform boundedness theorem is extended to functions which are not necessarily continuous, including various derivatives. The closed graph theorem is strictly generalized in two separate ways, and applications are presented using these generalizations. An invariance property of separately continuous functions is given. Cluster sets are studied in connection with separate continuity, and various results are presented concerning locally bounded functions.
- Full Text:
- Date Issued: 2002
Convergence of old and new: a case study analysis of the development online by a South African radio station: Radiosondergrense/www.rsg.co.za
- Authors: Vasques, Vanessa Claudia
- Date: 2002
- Subjects: Radio stations -- South Africa , Radio stations -- South Africa -- Marketing , Radio stations -- Computer network resources , Radiosondergrense
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3498 , http://hdl.handle.net/10962/d1003913 , Radio stations -- South Africa , Radio stations -- South Africa -- Marketing , Radio stations -- Computer network resources , Radiosondergrense
- Description: This thesis is a case study analysis of the dream one radio station had about creating something new and unique on the Internet. RadioSonderGrense (RSG), an Afrikaans South African radio station, saw opportunities for themselves as a radio station on the Internet and put enormous resources and man-power into their venture. Their vision of what the Internet could bring to their radio station, and what they could bring to a website set the ground for creative and innovative thought. This dissertation is an examination of whether the Internet lived up to the expectations RSG had for it, and whether they were able to use their resources (in terms of their audience, their advertisers and the uniqueness of radio) to create something new and never seen before. The foremost aim of this dissertation is to shed some light onto the up-to-now under researched area of why radio stations have begun to develop on the Internet. Through the analysis of RSG, their comes to this subject some new thoughts and ideas about the convergence of these two mediums. RSG, and radio in general, are examined historically, practically and in comparison to the Internet. This is done in order to fully grasp the project that RSG had set for themselves and to realize where they had come from and where they hoped to go. It is argued that although RSG had hoped for great things, their innovative thought was not enough to guarantee them their dreams. They were not able to fully utilize the resources available to them in combination with what the Internet could offer them to fulfill the expectations they had for themselves. The foremost conclusion is that although RSG were able to envisage what the Internet could add to the radio station, they fell short of giving their listeners, users and advertisers a tool which could make the RSG website truly unique. Their website gives the user some interesting and useful applications, but it does not make full use of what the Internet and radio together could create.
- Full Text:
- Date Issued: 2002
- Authors: Vasques, Vanessa Claudia
- Date: 2002
- Subjects: Radio stations -- South Africa , Radio stations -- South Africa -- Marketing , Radio stations -- Computer network resources , Radiosondergrense
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3498 , http://hdl.handle.net/10962/d1003913 , Radio stations -- South Africa , Radio stations -- South Africa -- Marketing , Radio stations -- Computer network resources , Radiosondergrense
- Description: This thesis is a case study analysis of the dream one radio station had about creating something new and unique on the Internet. RadioSonderGrense (RSG), an Afrikaans South African radio station, saw opportunities for themselves as a radio station on the Internet and put enormous resources and man-power into their venture. Their vision of what the Internet could bring to their radio station, and what they could bring to a website set the ground for creative and innovative thought. This dissertation is an examination of whether the Internet lived up to the expectations RSG had for it, and whether they were able to use their resources (in terms of their audience, their advertisers and the uniqueness of radio) to create something new and never seen before. The foremost aim of this dissertation is to shed some light onto the up-to-now under researched area of why radio stations have begun to develop on the Internet. Through the analysis of RSG, their comes to this subject some new thoughts and ideas about the convergence of these two mediums. RSG, and radio in general, are examined historically, practically and in comparison to the Internet. This is done in order to fully grasp the project that RSG had set for themselves and to realize where they had come from and where they hoped to go. It is argued that although RSG had hoped for great things, their innovative thought was not enough to guarantee them their dreams. They were not able to fully utilize the resources available to them in combination with what the Internet could offer them to fulfill the expectations they had for themselves. The foremost conclusion is that although RSG were able to envisage what the Internet could add to the radio station, they fell short of giving their listeners, users and advertisers a tool which could make the RSG website truly unique. Their website gives the user some interesting and useful applications, but it does not make full use of what the Internet and radio together could create.
- Full Text:
- Date Issued: 2002
Counter-hair/gemonies: hair as a site of black identity struggle in post-apartheid South Africa
- Authors: Morey, Yvette Vivienne
- Date: 2002
- Subjects: Hairstyles -- South Africa , Women, Black -- Race identity , Hair -- Social aspects -- South Africa , Beauty, Personal -- Social aspects -- South Africa , Hairdressing of Black people
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3024 , http://hdl.handle.net/10962/d1002533 , Hairstyles -- South Africa , Women, Black -- Race identity , Hair -- Social aspects -- South Africa , Beauty, Personal -- Social aspects -- South Africa , Hairdressing of Black people
- Description: This thesis aims to allow the meanings engendered by various black hairstyle choices to emerge as discursive texts with which to further explore issues of black identity in post-apartheid South Africa. It seeks to identify what, if any, new discursive spaces and possibilities are operational in the post-apartheid capitalist context, and how identities are moulded by, and in tum, influence these possibilities. Operating within a discourse analytic approach, this research did not intend to establish fixed and generalisable notions of identity, but by unpacking the discursive baggage attached to historically loaded subjectivities it is concerned with reflecting identity as an ongoing and reflexive project. Entailing a diverse selection of texts, the analysis includes self-generated texts (stemming from interviews, a focus group and participant observation), and public domain texts (stemming from online and print media articles). Chapters 5 - 9 constitute the textual analysis. Using a consumer hair care product as a text, chapter 5 serves as an introduction to discourses surrounding black hair as a variously constructed object. This focus is concerned, more specifically, with the construction of black hair as a 'natural' object in chapter 6. Chapter 7 examines black hair gemonies and the " problematic classification and de/classification of class and consumer identities. Discourses pertaining to the construction and positioning of gendered and sexual subjectivities are explored in chapter 8. Finally, chapter 9 is concerned with the operations of discourses as they function to construct essentialised or hybrid conceptions of identity. The implications for black identity construction in post-apartheid South Africa are discussed in chapter 10 alongside a deconstruction of the research method and researcher positioning.
- Full Text:
- Date Issued: 2002
- Authors: Morey, Yvette Vivienne
- Date: 2002
- Subjects: Hairstyles -- South Africa , Women, Black -- Race identity , Hair -- Social aspects -- South Africa , Beauty, Personal -- Social aspects -- South Africa , Hairdressing of Black people
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3024 , http://hdl.handle.net/10962/d1002533 , Hairstyles -- South Africa , Women, Black -- Race identity , Hair -- Social aspects -- South Africa , Beauty, Personal -- Social aspects -- South Africa , Hairdressing of Black people
- Description: This thesis aims to allow the meanings engendered by various black hairstyle choices to emerge as discursive texts with which to further explore issues of black identity in post-apartheid South Africa. It seeks to identify what, if any, new discursive spaces and possibilities are operational in the post-apartheid capitalist context, and how identities are moulded by, and in tum, influence these possibilities. Operating within a discourse analytic approach, this research did not intend to establish fixed and generalisable notions of identity, but by unpacking the discursive baggage attached to historically loaded subjectivities it is concerned with reflecting identity as an ongoing and reflexive project. Entailing a diverse selection of texts, the analysis includes self-generated texts (stemming from interviews, a focus group and participant observation), and public domain texts (stemming from online and print media articles). Chapters 5 - 9 constitute the textual analysis. Using a consumer hair care product as a text, chapter 5 serves as an introduction to discourses surrounding black hair as a variously constructed object. This focus is concerned, more specifically, with the construction of black hair as a 'natural' object in chapter 6. Chapter 7 examines black hair gemonies and the " problematic classification and de/classification of class and consumer identities. Discourses pertaining to the construction and positioning of gendered and sexual subjectivities are explored in chapter 8. Finally, chapter 9 is concerned with the operations of discourses as they function to construct essentialised or hybrid conceptions of identity. The implications for black identity construction in post-apartheid South Africa are discussed in chapter 10 alongside a deconstruction of the research method and researcher positioning.
- Full Text:
- Date Issued: 2002
Critical literacy in South Africa : possibilities and constraints in 2002
- Authors: Prinsloo, J , Janks, H
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6330 , http://hdl.handle.net/10962/d1008475
- Description: This article examines the Curriculum documents produced in South Africa since the election of a democratic government in 1994 in order to consider the possibilities they create for the inclusion of critical literacy in the teaching of home languages. This discussion is set against an analysis of the apartheid curriculum documents prior to 1994 and a consideration of the ongoing inequalities in the provision of human and material resources across the system. Despite real constraints with regard to implementation, it is argued that the new Curriculum effects a significant break with the past and makes a positive contribution to transforming language education.
- Full Text:
- Date Issued: 2002
- Authors: Prinsloo, J , Janks, H
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6330 , http://hdl.handle.net/10962/d1008475
- Description: This article examines the Curriculum documents produced in South Africa since the election of a democratic government in 1994 in order to consider the possibilities they create for the inclusion of critical literacy in the teaching of home languages. This discussion is set against an analysis of the apartheid curriculum documents prior to 1994 and a consideration of the ongoing inequalities in the provision of human and material resources across the system. Despite real constraints with regard to implementation, it is argued that the new Curriculum effects a significant break with the past and makes a positive contribution to transforming language education.
- Full Text:
- Date Issued: 2002
Cyclic voltammetric studies of octabutylthiophthalo-cyaninato-cobalt (II) and its self-assembled monolayer (SAM) on gold electrode
- Ozoemena, Kenneth, Westbroek, Philippe, Nyokong, Tebello
- Authors: Ozoemena, Kenneth , Westbroek, Philippe , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289567 , vital:56650 , xlink:href="https://doi.org/10.1142/S1088424602000130"
- Description: The synthesis of thiol-derivatized cobalt phthalocyanine complex, 2,3,9,10,16,17,23,24-octa (butylthiophthalocyaninatocobalt(II) (CoOBTPc) is described. Cyclic voltammetric data of this complex in DMF showed five quasi-reversible and reversible, diffusion-controlled redox couples, comprising both the phthalocyanine ring and central metal redox processes. The CoOBTPc complex forms a self-assembled monolayer (SAM) on gold electrode. The investigation of the integrity of this SAM, using the established cyclic voltammetric methods in aqueous alkaline solutions, gave evidence about the formation of a stable and easily reproducible monolayer. However, due to its susceptibility to destruction via oxidative and reductive desorptions, its potential application as an electrochemical sensor in alkaline pH is limited to a potential window of between −0.20 and +0.55 V vs Ag/AgCl.
- Full Text:
- Date Issued: 2002
- Authors: Ozoemena, Kenneth , Westbroek, Philippe , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289567 , vital:56650 , xlink:href="https://doi.org/10.1142/S1088424602000130"
- Description: The synthesis of thiol-derivatized cobalt phthalocyanine complex, 2,3,9,10,16,17,23,24-octa (butylthiophthalocyaninatocobalt(II) (CoOBTPc) is described. Cyclic voltammetric data of this complex in DMF showed five quasi-reversible and reversible, diffusion-controlled redox couples, comprising both the phthalocyanine ring and central metal redox processes. The CoOBTPc complex forms a self-assembled monolayer (SAM) on gold electrode. The investigation of the integrity of this SAM, using the established cyclic voltammetric methods in aqueous alkaline solutions, gave evidence about the formation of a stable and easily reproducible monolayer. However, due to its susceptibility to destruction via oxidative and reductive desorptions, its potential application as an electrochemical sensor in alkaline pH is limited to a potential window of between −0.20 and +0.55 V vs Ag/AgCl.
- Full Text:
- Date Issued: 2002
De-scribing the Timaeus: a transgression of the (phal) logocentric convention that discourse has only one form, language
- Authors: Ord, Jennifer
- Date: 2002
- Subjects: Discourse analysis , Art -- Philosophy
- Language: English
- Type: Thesis , Masters , MTech (Fine Art)
- Identifier: vital:10763 , http://hdl.handle.net/10948/115 , Discourse analysis , Art -- Philosophy
- Description: Like writing, art making is primarily a means of human expression, a means of communication – both “allow us to categorize our (inner and outer) environment as represented by symbols” (Appignanesi, 1999: 7). Yet it is language in the traditional Western garb of rational, philosophical discourse that has been perceived as the primary means of manifesting knowledge and positing truth, not only regarding the character of human existence, but also the nature of art. This infers the acceptance of both works as literally “truth of things”, and of “a language of reason” that “perfectly represents the real world” (Appignanesi, 1999: 77). Going against the grain of this traditional bias, Jacques Derrida holds that, firstly, “human knowledge is not as controllable or as cogent as Western thinkers would have it”: secondly, that language functions in “subtle and often contradictory ways” thus rendering certainty, truth, and perfect representation ever elusive to us (Lye, 1997: 2); and, thirdly, that “practices of interpretation which include art but are not limited to language, are extended discourses” (Appignanesi, 1999: 79). So, the “work of reason” (or rationalism) in this sense, is no longer the definitive “voice” of authority when it comes to ascribing meaning, proclaiming a message, defining truth, etc. Having the grip of its authority loosened and thus its rigid, imposing borders opened up, the communication of knowledge as a form of “aesthetic fiction” (Megill, 1987: 265) is allowed entry into the rarefied field of philosophical discourse. Moreover, if visual art (one such “aesthetic fiction”) is a process of sign-making, as is written and spoken language; if it therefore constitutes a signifying system, as does written and spoken language (Bal and Bryson in Preziosi, 1998: 242); and, if art is not just about autonomous, in-house formalism, then can it not, in any case, validly offer a form for discourse, albeit a different kind of discourse, a discourse that is not “truth seeking” (Sim, 1992: 33)? Here, the maker of the proposed artwork-asdiscourse would not be attempting to establish the truth or falsity of a philosophical position, but, as Derrida would have it, create a form which, without mimicry, would evocatively allude to Plato, his “deconstructor” and the maker of the proposed artwork. Discourse in this sense, then, would generate “active interpretation… infinite free association” (Megill, 1987: 283), because, as in Derrida’s writing, interpretation no longer aims at “the reconciliation or unification of warring truths (Sim, 1992: 10); in other words, it breaks with the (phal)logocentric tradition of discourse as dialectical and becomes questioning without closure. For visual art to enter the exalted arena of philosophical discourse, it cannot be selfreflexive in the Greenbergian or formalist sense – it has to be about something philosophical and this ‘something’ will be a deconstructive response to Plato’s doctrine of the two worlds in the Timaeus. What I propose presenting, then, is an imagographic rather than (phal)logocentric exposition of philosophical content where the aim is not to shape a certainty or to infer an absolute presence or essence of anything, but rather to suggest traces of the maker of the artwork reading Derrida, reading Plato. The proposed artwork as a response to texts will thus be a “pre-text” of my own endeavour.
- Full Text:
- Date Issued: 2002
- Authors: Ord, Jennifer
- Date: 2002
- Subjects: Discourse analysis , Art -- Philosophy
- Language: English
- Type: Thesis , Masters , MTech (Fine Art)
- Identifier: vital:10763 , http://hdl.handle.net/10948/115 , Discourse analysis , Art -- Philosophy
- Description: Like writing, art making is primarily a means of human expression, a means of communication – both “allow us to categorize our (inner and outer) environment as represented by symbols” (Appignanesi, 1999: 7). Yet it is language in the traditional Western garb of rational, philosophical discourse that has been perceived as the primary means of manifesting knowledge and positing truth, not only regarding the character of human existence, but also the nature of art. This infers the acceptance of both works as literally “truth of things”, and of “a language of reason” that “perfectly represents the real world” (Appignanesi, 1999: 77). Going against the grain of this traditional bias, Jacques Derrida holds that, firstly, “human knowledge is not as controllable or as cogent as Western thinkers would have it”: secondly, that language functions in “subtle and often contradictory ways” thus rendering certainty, truth, and perfect representation ever elusive to us (Lye, 1997: 2); and, thirdly, that “practices of interpretation which include art but are not limited to language, are extended discourses” (Appignanesi, 1999: 79). So, the “work of reason” (or rationalism) in this sense, is no longer the definitive “voice” of authority when it comes to ascribing meaning, proclaiming a message, defining truth, etc. Having the grip of its authority loosened and thus its rigid, imposing borders opened up, the communication of knowledge as a form of “aesthetic fiction” (Megill, 1987: 265) is allowed entry into the rarefied field of philosophical discourse. Moreover, if visual art (one such “aesthetic fiction”) is a process of sign-making, as is written and spoken language; if it therefore constitutes a signifying system, as does written and spoken language (Bal and Bryson in Preziosi, 1998: 242); and, if art is not just about autonomous, in-house formalism, then can it not, in any case, validly offer a form for discourse, albeit a different kind of discourse, a discourse that is not “truth seeking” (Sim, 1992: 33)? Here, the maker of the proposed artwork-asdiscourse would not be attempting to establish the truth or falsity of a philosophical position, but, as Derrida would have it, create a form which, without mimicry, would evocatively allude to Plato, his “deconstructor” and the maker of the proposed artwork. Discourse in this sense, then, would generate “active interpretation… infinite free association” (Megill, 1987: 283), because, as in Derrida’s writing, interpretation no longer aims at “the reconciliation or unification of warring truths (Sim, 1992: 10); in other words, it breaks with the (phal)logocentric tradition of discourse as dialectical and becomes questioning without closure. For visual art to enter the exalted arena of philosophical discourse, it cannot be selfreflexive in the Greenbergian or formalist sense – it has to be about something philosophical and this ‘something’ will be a deconstructive response to Plato’s doctrine of the two worlds in the Timaeus. What I propose presenting, then, is an imagographic rather than (phal)logocentric exposition of philosophical content where the aim is not to shape a certainty or to infer an absolute presence or essence of anything, but rather to suggest traces of the maker of the artwork reading Derrida, reading Plato. The proposed artwork as a response to texts will thus be a “pre-text” of my own endeavour.
- Full Text:
- Date Issued: 2002
Deconstructive discourse analysis: extending the methodological conversation
- Authors: Macleod, Catriona I
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6259 , http://hdl.handle.net/10962/d1007877 , http://journals.sagepub.com/doi/abs/10.1177/008124630203200103
- Description: Discourse analysis is increasingly becoming a methodology of preference amongst qualitative researchers. There is a danger, however, of it being viewed as a bounded and uncontested domain of research practice. As discourse analysis is inextricably linked with theoretical issues, it is a dynamic practice that is constantly in a process of revision. In this paper I reflect on some of the conceptualisations undergirding the notion of discourse – conceptualisations that have important implications in terms of how the practice of discourse analysis proceeds. I highlight some of the dualisms that may plague discourse analysis, and offer some solutions to these. Finally, I outline the deconstructive discourse analysis that I utilised in my doctoral work. The purpose of the latter is not to provide a recipe of methodology, but to illustrate how elements of various theorists’ work (in this case Foucault, Derrida and Parker) may be profitably drawn together to perform specific discourse analytic work. , Rhodes University
- Full Text:
- Date Issued: 2002
- Authors: Macleod, Catriona I
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6259 , http://hdl.handle.net/10962/d1007877 , http://journals.sagepub.com/doi/abs/10.1177/008124630203200103
- Description: Discourse analysis is increasingly becoming a methodology of preference amongst qualitative researchers. There is a danger, however, of it being viewed as a bounded and uncontested domain of research practice. As discourse analysis is inextricably linked with theoretical issues, it is a dynamic practice that is constantly in a process of revision. In this paper I reflect on some of the conceptualisations undergirding the notion of discourse – conceptualisations that have important implications in terms of how the practice of discourse analysis proceeds. I highlight some of the dualisms that may plague discourse analysis, and offer some solutions to these. Finally, I outline the deconstructive discourse analysis that I utilised in my doctoral work. The purpose of the latter is not to provide a recipe of methodology, but to illustrate how elements of various theorists’ work (in this case Foucault, Derrida and Parker) may be profitably drawn together to perform specific discourse analytic work. , Rhodes University
- Full Text:
- Date Issued: 2002
Design, development and analysis of the friction stir welding process
- Authors: Blignault, Calvin
- Date: 2002
- Subjects: Friction welding
- Language: English
- Type: Thesis , Masters , MTech (Mechanical Engineering)
- Identifier: vital:10809 , http://hdl.handle.net/10948/1350 , Friction welding
- Description: The development of a CNC-based technology FSW machine to accurately produce friction stir weld samples that can be analyzed for research purposes is implemented and discussed. A process diagnosis and control scheme to improve the process monitoring and weld evaluation capabilities of an FSW machine are proposed and implemented. Basic CNC-based hardware implementation such as optical encoders and inverters for process control are explained and verified. The control scheme and framework of interfaces to the digital I/O cards for PC user interface are explained. An advanced monitoring system which senses process performance parameters such as tool temperature, 3-axis tool forces, torque and spindle speed are explained. Mechanical designs and manufacturing techniques such as tool, clamp and backing plate designs are explained and verified. The process parameters for quality optimization are investigated and optimized by making use of Correlation and Regression Analysis. The statistical data and analytical relationships between welding parameters (independent) and each of the performance parameters (dependent) are obtained and used to simulate the machining process. The weld research samples are tested for strength and integrity making use of various scientific testing techniques. The reliability of the samples are also evaluated and compared to that of other institutions. Process variables and the optimum operating range of the Friction Stir Welding machine is determined and a framework for further research into weld quality optimization is set.
- Full Text:
- Date Issued: 2002
- Authors: Blignault, Calvin
- Date: 2002
- Subjects: Friction welding
- Language: English
- Type: Thesis , Masters , MTech (Mechanical Engineering)
- Identifier: vital:10809 , http://hdl.handle.net/10948/1350 , Friction welding
- Description: The development of a CNC-based technology FSW machine to accurately produce friction stir weld samples that can be analyzed for research purposes is implemented and discussed. A process diagnosis and control scheme to improve the process monitoring and weld evaluation capabilities of an FSW machine are proposed and implemented. Basic CNC-based hardware implementation such as optical encoders and inverters for process control are explained and verified. The control scheme and framework of interfaces to the digital I/O cards for PC user interface are explained. An advanced monitoring system which senses process performance parameters such as tool temperature, 3-axis tool forces, torque and spindle speed are explained. Mechanical designs and manufacturing techniques such as tool, clamp and backing plate designs are explained and verified. The process parameters for quality optimization are investigated and optimized by making use of Correlation and Regression Analysis. The statistical data and analytical relationships between welding parameters (independent) and each of the performance parameters (dependent) are obtained and used to simulate the machining process. The weld research samples are tested for strength and integrity making use of various scientific testing techniques. The reliability of the samples are also evaluated and compared to that of other institutions. Process variables and the optimum operating range of the Friction Stir Welding machine is determined and a framework for further research into weld quality optimization is set.
- Full Text:
- Date Issued: 2002
Design, evaluation and comparison of evolution and reinforcement learning models
- Authors: Mclean, Clinton Brett
- Date: 2002
- Subjects: Evolutionary computation Neural networks (Computer science) Reinforcement learning
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:4625 , http://hdl.handle.net/10962/d1006493
- Description: This work presents the design, evaluation and comparison of evolution and reinforcement learning models, in isolation and combined in Darwinian and Lamarckian frameworks, with a particular emphasis being placed on their adaptive nature in response to environments that become increasingly unstable. Our ultimate objective is to determine whether hybrid models of evolution and learning can demonstrate adaptive qualities beyond those of such models when applied in isolation. This work demonstrates the limitations of evolution, reinforcement learning and Lamarckian models in dealing with increasingly unstable environments, while noting the effective adaptive nature of a Darwinian model to assimilate increasing levels of instability. This is shown to be a result of the Darwinian evolution model's ability to separate learning at two levels, the population's experience of the environment over the course of many generations and the individual's experience of the environment over the course of its lifetime. Thus, knowledge relating to the general characteristics of the environment over many generations can be maintained in the population's genotypes with phenotype (reinforcement) learning being utilized to adapt a particular agent to the particular characteristics of its environment. Lamarckian evolution, though, is shown to demonstrate adaptive characteristics that are highly effective in response to the stable environments. Selection and reproduction combined with reinforcement learning creates a model that has the ability to utilize useful knowledge produced by reinforcements, as opposed to random mutations, to accelerate the search process. As a result the influence of individual learning on the populations evolution is shown to be more successful when applied in the more direct Lamarckian form. Based on our results demonstrating the success of Lamarckian strategies in stable environments and Darwinian strategies in unstable environments, hybrid Darwinian/Lamarckian models are created with a view towards combining the advantages of both forms of evolution to produce a superior adaptive capability. Our investigation demonstrates that such hybrid models can effectively combine the adaptive advantageous of both Darwinian and Lamarckian evolution to provide a more effective capability of adapting to a range of conditions, from stable to unstable, appropriately adjusting the required degree of inheritance in response to the requirements of the environment.
- Full Text:
- Date Issued: 2002
- Authors: Mclean, Clinton Brett
- Date: 2002
- Subjects: Evolutionary computation Neural networks (Computer science) Reinforcement learning
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:4625 , http://hdl.handle.net/10962/d1006493
- Description: This work presents the design, evaluation and comparison of evolution and reinforcement learning models, in isolation and combined in Darwinian and Lamarckian frameworks, with a particular emphasis being placed on their adaptive nature in response to environments that become increasingly unstable. Our ultimate objective is to determine whether hybrid models of evolution and learning can demonstrate adaptive qualities beyond those of such models when applied in isolation. This work demonstrates the limitations of evolution, reinforcement learning and Lamarckian models in dealing with increasingly unstable environments, while noting the effective adaptive nature of a Darwinian model to assimilate increasing levels of instability. This is shown to be a result of the Darwinian evolution model's ability to separate learning at two levels, the population's experience of the environment over the course of many generations and the individual's experience of the environment over the course of its lifetime. Thus, knowledge relating to the general characteristics of the environment over many generations can be maintained in the population's genotypes with phenotype (reinforcement) learning being utilized to adapt a particular agent to the particular characteristics of its environment. Lamarckian evolution, though, is shown to demonstrate adaptive characteristics that are highly effective in response to the stable environments. Selection and reproduction combined with reinforcement learning creates a model that has the ability to utilize useful knowledge produced by reinforcements, as opposed to random mutations, to accelerate the search process. As a result the influence of individual learning on the populations evolution is shown to be more successful when applied in the more direct Lamarckian form. Based on our results demonstrating the success of Lamarckian strategies in stable environments and Darwinian strategies in unstable environments, hybrid Darwinian/Lamarckian models are created with a view towards combining the advantages of both forms of evolution to produce a superior adaptive capability. Our investigation demonstrates that such hybrid models can effectively combine the adaptive advantageous of both Darwinian and Lamarckian evolution to provide a more effective capability of adapting to a range of conditions, from stable to unstable, appropriately adjusting the required degree of inheritance in response to the requirements of the environment.
- Full Text:
- Date Issued: 2002
Detection of neurotransmitters using metallophthalocyanines as electrocatalysts
- Authors: Oni, Joshua Idowu
- Date: 2002
- Subjects: Neurotransmitters Electrochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4435 , http://hdl.handle.net/10962/d1007470
- Description: Some metallophthalocyanine complexes were synthesized and their catalytic activities towards the detection and quantification of the neurotransmitters dopamine, serotonin and histamine were investigated. The study of the possible interaction between these transmitter substances and the metallophthalocyanine complexes was undertaken. Dopamine, serotonin and histamine formed complexes with Iron (II) tetrasulfophthalocyanine. The rate and equilibrium constants obtained for the coordination are in the range of values reported in the literature for ligand coordination to iron phthalocyanine complexes. Carbon paste electrodes of millimetric diameters modified with Iron (II) tetrasulfophthalocyanine exhibited good electro catalytic activity towards the detection and analysis of dopamine and serotonin while at the same time eliminated the problem of interference posed by ascorbic acid in the electrochemical analysis of neurotransmitters. A detection limit of the order of 10-6 mol dm-3 was obtained for both dopamine and serotonin at the modified electrodes. Carbon paste ultra micro electrodes modified with iron (II) tetrasulfophthalocyanine were also used for the detection of dopamine and serotonin as well as the simultaneous determination of dopamine and ascorbic acid in a mixture. The detection limit obtained for dopamine at the ultra microelectrode was 4.2xlO-7 mol dm-3 The electrode kinetics of vitamin BI as well as the stability of the electrode towards its determination was improved upon by modifying carbon paste electrodes with manganese phthalocyanine. The modified electrodes were used for the analysis of vitamin BI in tablets.
- Full Text:
- Date Issued: 2002
- Authors: Oni, Joshua Idowu
- Date: 2002
- Subjects: Neurotransmitters Electrochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4435 , http://hdl.handle.net/10962/d1007470
- Description: Some metallophthalocyanine complexes were synthesized and their catalytic activities towards the detection and quantification of the neurotransmitters dopamine, serotonin and histamine were investigated. The study of the possible interaction between these transmitter substances and the metallophthalocyanine complexes was undertaken. Dopamine, serotonin and histamine formed complexes with Iron (II) tetrasulfophthalocyanine. The rate and equilibrium constants obtained for the coordination are in the range of values reported in the literature for ligand coordination to iron phthalocyanine complexes. Carbon paste electrodes of millimetric diameters modified with Iron (II) tetrasulfophthalocyanine exhibited good electro catalytic activity towards the detection and analysis of dopamine and serotonin while at the same time eliminated the problem of interference posed by ascorbic acid in the electrochemical analysis of neurotransmitters. A detection limit of the order of 10-6 mol dm-3 was obtained for both dopamine and serotonin at the modified electrodes. Carbon paste ultra micro electrodes modified with iron (II) tetrasulfophthalocyanine were also used for the detection of dopamine and serotonin as well as the simultaneous determination of dopamine and ascorbic acid in a mixture. The detection limit obtained for dopamine at the ultra microelectrode was 4.2xlO-7 mol dm-3 The electrode kinetics of vitamin BI as well as the stability of the electrode towards its determination was improved upon by modifying carbon paste electrodes with manganese phthalocyanine. The modified electrodes were used for the analysis of vitamin BI in tablets.
- Full Text:
- Date Issued: 2002
Determining and improving the level of service quality at International Healthcare Distributors
- Authors: Vassen, Ansuya
- Date: 2002
- Subjects: Pharmaceutical industry -- South Africa -- Port Elizabeth -- Quality control
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10897 , http://hdl.handle.net/10948/82 , Pharmaceutical industry -- South Africa -- Port Elizabeth -- Quality control
- Description: The levels of service quality at International Healthcare Distributors (IHD) have been determined. Service quality in organisations require a strong emphasis on customer service and service delivery processes. The main area of this study focuses on the need for appropriate levels and criteria of service quality that will satisfy customers of pharmaceutical distributors. Various determinants affecting service quality levels have been discussed. The nature of service quality has been outlined and customer expectation standards have been determined. Customer satisfaction versus service quality has been discussed and the consumers’ perceptions towards service quality have been identified. Obstacles to attaining service quality have been described and potential causes of service quality shortfalls have been defined. Various surveys were studied to determine the implementation of service quality dimensions in a variety of disciplines. A sample was taken from the IHD customer base and a questionnaire was designed and distributed to the customers. The questionnaire examined five dimensions, tangibility, reliability, responsiveness, assurance and empathy. There was a hundred percent response rate. The results indicated that the tangibility dimension was highest in terms of customer agreement and reliability the lowest. The results of the questionnaire have proven that two of the hypotheses are negative and one positive. Concluding remarks and recommendations were highlighted and it is evident that IHD needs to improve its level of service quality in order to meet their customer requirements.
- Full Text:
- Date Issued: 2002
- Authors: Vassen, Ansuya
- Date: 2002
- Subjects: Pharmaceutical industry -- South Africa -- Port Elizabeth -- Quality control
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10897 , http://hdl.handle.net/10948/82 , Pharmaceutical industry -- South Africa -- Port Elizabeth -- Quality control
- Description: The levels of service quality at International Healthcare Distributors (IHD) have been determined. Service quality in organisations require a strong emphasis on customer service and service delivery processes. The main area of this study focuses on the need for appropriate levels and criteria of service quality that will satisfy customers of pharmaceutical distributors. Various determinants affecting service quality levels have been discussed. The nature of service quality has been outlined and customer expectation standards have been determined. Customer satisfaction versus service quality has been discussed and the consumers’ perceptions towards service quality have been identified. Obstacles to attaining service quality have been described and potential causes of service quality shortfalls have been defined. Various surveys were studied to determine the implementation of service quality dimensions in a variety of disciplines. A sample was taken from the IHD customer base and a questionnaire was designed and distributed to the customers. The questionnaire examined five dimensions, tangibility, reliability, responsiveness, assurance and empathy. There was a hundred percent response rate. The results indicated that the tangibility dimension was highest in terms of customer agreement and reliability the lowest. The results of the questionnaire have proven that two of the hypotheses are negative and one positive. Concluding remarks and recommendations were highlighted and it is evident that IHD needs to improve its level of service quality in order to meet their customer requirements.
- Full Text:
- Date Issued: 2002
Development of nickel-selective molecularly imprinted polymers
- Tshikhudo, Tshinyadzo Robert
- Authors: Tshikhudo, Tshinyadzo Robert
- Date: 2002 , 2013-07-25
- Subjects: Imprinted polymers , Imprinted polymers -- Synthesis , Molecular imprinting , Nickel , Nickel -- Metallurgy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4292 , http://hdl.handle.net/10962/d1004449 , Imprinted polymers , Imprinted polymers -- Synthesis , Molecular imprinting , Nickel , Nickel -- Metallurgy
- Description: A series of eight novel bidentate ligands, designed for use in the construction of nickel-selective molecularly imprinted polymers (MIP's), have been prepared. The synthetic pathway was established by retrosynthetic analysis of the target molecules to the readily available precursors, pyridine-2-carbaldehyde (or 6-methylpyridine-2-carbaldehyde) and ethyl bromoacetate. The ligands were designed to contain an allyl group for co-polymerisation and amine and pyridyl nitrogen donors, located to permit the formation of 5-membered nickel chelates. The eight novel ligands and their respective precursors were characterized by elemental (high-resolution MS) and spectroscopic (IR and ¹H and ¹³C NMR) analysis. High resolution electron-impact mass spectrometry has also been used, together with B/E linked scan data, to explore the fragmentation patterns of selected ligands. The various nickel(ll) complexes were analyzed using spectroscopic techniques and, in some cases, elemental analysis; computer modelling has also been used to explore conformational effects and complex stability. Numerous MIP's, containing nickel(II) complexes of the bidentate ligands, have been prepared, using ethylene glycol dimethylacrylate (EGDMA) as the cross-linker, azobis(isobutyronitrile) (AlBN) as the polymerization initiator and MeOH as the porogenic solvent. The template nickel(II) ions were leached out with conc. HCI, and the nickel(II) selectivity [in the presence of Fe(Ill)] of the nickel-imprinted polymers was examined by ICP-MS analysis. The ICP-MS data indicate that the MIP's examined exhibit extremely high selectivity for nickel over iron. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2002
- Authors: Tshikhudo, Tshinyadzo Robert
- Date: 2002 , 2013-07-25
- Subjects: Imprinted polymers , Imprinted polymers -- Synthesis , Molecular imprinting , Nickel , Nickel -- Metallurgy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4292 , http://hdl.handle.net/10962/d1004449 , Imprinted polymers , Imprinted polymers -- Synthesis , Molecular imprinting , Nickel , Nickel -- Metallurgy
- Description: A series of eight novel bidentate ligands, designed for use in the construction of nickel-selective molecularly imprinted polymers (MIP's), have been prepared. The synthetic pathway was established by retrosynthetic analysis of the target molecules to the readily available precursors, pyridine-2-carbaldehyde (or 6-methylpyridine-2-carbaldehyde) and ethyl bromoacetate. The ligands were designed to contain an allyl group for co-polymerisation and amine and pyridyl nitrogen donors, located to permit the formation of 5-membered nickel chelates. The eight novel ligands and their respective precursors were characterized by elemental (high-resolution MS) and spectroscopic (IR and ¹H and ¹³C NMR) analysis. High resolution electron-impact mass spectrometry has also been used, together with B/E linked scan data, to explore the fragmentation patterns of selected ligands. The various nickel(ll) complexes were analyzed using spectroscopic techniques and, in some cases, elemental analysis; computer modelling has also been used to explore conformational effects and complex stability. Numerous MIP's, containing nickel(II) complexes of the bidentate ligands, have been prepared, using ethylene glycol dimethylacrylate (EGDMA) as the cross-linker, azobis(isobutyronitrile) (AlBN) as the polymerization initiator and MeOH as the porogenic solvent. The template nickel(II) ions were leached out with conc. HCI, and the nickel(II) selectivity [in the presence of Fe(Ill)] of the nickel-imprinted polymers was examined by ICP-MS analysis. The ICP-MS data indicate that the MIP's examined exhibit extremely high selectivity for nickel over iron. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2002
Diamondback Moth, Plutella xylostella (L.), (Lepidoptera: Plutellidae ), and Other Insects of Canola, Brassica napus L., in Gauteng Province, South Africa
- Authors: Mosiane, M S
- Date: 2002
- Subjects: Plutellidae , Plutellidae -- South Africa -- Gauteng , Rape (Plant) -- South Africa -- Gauteng , Canola , Plant parasites
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5937 , http://hdl.handle.net/10962/d1018250
- Description: Canola, Brassics napus L. is a relatively new crop in South Africa. Insect pests have not yet been a major problem, but the notorious brassica specialist, diamondback moth (DBM), Plutella xylostella (L.) (Plutellidae) is establishing itself as a serious pest of this crop. DBM is the most important insect pest of plants from the family Brassicaceae throughout the world. It has developed resistance to all chemical pesticides used against it in the field and to toxins of the bacterium Bacillus thuringiensis. The pest status of DBM in South Africa is lower than in other countries with similar climates. However, due to indiscriminate use of pesticides, local populations of DBM are showing signs of resistance. An initial survey has indicated that in addition to DBM, canola is also attacked by aphids, Myzus persicae (Sulzer), Brevicoryne brassicae (L.), Lipaphis e1ysimi (Kaltenbach), (Aphiade), thrips, Thrips tabaci (Lindeman) and other pests mostly brassica specialists. The study was initiated to determine the composition of the community of insects found on canola, the seasonal phenology of DBM populations in canola, and the composition, relative abundance and seasonality of its parasitoids. Monitoring of the insects was carried out at weekly intervals for three years at Rietondale and Bapsfontein in Gauteng province of South Africa. Berlese funnels have been found to be useful in extracting insects from plants, and were used to indicate the presence ofDBM larvae and other insects found on canola. Adults of DBM were monitored with synthetic pheromone traps; larval and pupal populations were monitored by scouting canola plants. Samples of larvae, pupae and parasitoid cocoons were brought into the laboratory. Parasitoids that emerged were identified and their incidence recorded. Monolepta cf bifasciata (Chrysomelidae) and Listroderes costrirostris (Schoener) (Curculionidae) were the most abundant of the coleopteran pests. (DBM) and Heliothis armigera (H.) (Noctuidae) were most abundant lepidopteran pests of Canola. There was a high proportion of first and second instar larvae as indicated by the results of the Berlese funnels as compared to visual scouting in Bapsfontein. From May to August the infestation level of DBM was high, reaching the maximum of 0.25 larvae per plant in June 1996, then declined and remained low for the rest of the season in Rietondale. From September to December for all three years of the study, the population levels Of DBM were high, reaching a maximum of 9.6larvae per plant in September 1997, and remained low from January to August in Bapsfontein. The number of adult moths per trap per week ranged from 0 to 91 in Rietondale, peaking in January 1996 and September 1997. There was no correlation between infestation levels and the pheromone trap catches. In contrast to Rietondale, there was a high correlation between pheromone trap catches and subsequent larval infestations at Bapsfontein. Although DBM infestation levels were generally low, parasitism levels often reached 100% caused by a complex of parasitoids. During the period of study, the following hymenopteran parasitoids were recorded: Cotesia plutellae (Kurdjumov) and Apanteles eriophyes (Nixon), Braconidae), both larval parasitoids, Diadegma mollipla (Holmgren) (Ichneumonidae), and Oomyzus sokolowskii (Kurdjumov) (Eulophidae), larval-pupal parasitoids, Diadromus collaris (Gravenhorst) (Ichneumonidae) pupal parasitoid, and the hyperparasitoids Mesochorus sp. (Ichneumonidae) and Pteromalus sp. (Pteromalidae). Cotesia plutellae was the most abundant parasitoid occurring throughout the year..
- Full Text:
- Date Issued: 2002
- Authors: Mosiane, M S
- Date: 2002
- Subjects: Plutellidae , Plutellidae -- South Africa -- Gauteng , Rape (Plant) -- South Africa -- Gauteng , Canola , Plant parasites
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5937 , http://hdl.handle.net/10962/d1018250
- Description: Canola, Brassics napus L. is a relatively new crop in South Africa. Insect pests have not yet been a major problem, but the notorious brassica specialist, diamondback moth (DBM), Plutella xylostella (L.) (Plutellidae) is establishing itself as a serious pest of this crop. DBM is the most important insect pest of plants from the family Brassicaceae throughout the world. It has developed resistance to all chemical pesticides used against it in the field and to toxins of the bacterium Bacillus thuringiensis. The pest status of DBM in South Africa is lower than in other countries with similar climates. However, due to indiscriminate use of pesticides, local populations of DBM are showing signs of resistance. An initial survey has indicated that in addition to DBM, canola is also attacked by aphids, Myzus persicae (Sulzer), Brevicoryne brassicae (L.), Lipaphis e1ysimi (Kaltenbach), (Aphiade), thrips, Thrips tabaci (Lindeman) and other pests mostly brassica specialists. The study was initiated to determine the composition of the community of insects found on canola, the seasonal phenology of DBM populations in canola, and the composition, relative abundance and seasonality of its parasitoids. Monitoring of the insects was carried out at weekly intervals for three years at Rietondale and Bapsfontein in Gauteng province of South Africa. Berlese funnels have been found to be useful in extracting insects from plants, and were used to indicate the presence ofDBM larvae and other insects found on canola. Adults of DBM were monitored with synthetic pheromone traps; larval and pupal populations were monitored by scouting canola plants. Samples of larvae, pupae and parasitoid cocoons were brought into the laboratory. Parasitoids that emerged were identified and their incidence recorded. Monolepta cf bifasciata (Chrysomelidae) and Listroderes costrirostris (Schoener) (Curculionidae) were the most abundant of the coleopteran pests. (DBM) and Heliothis armigera (H.) (Noctuidae) were most abundant lepidopteran pests of Canola. There was a high proportion of first and second instar larvae as indicated by the results of the Berlese funnels as compared to visual scouting in Bapsfontein. From May to August the infestation level of DBM was high, reaching the maximum of 0.25 larvae per plant in June 1996, then declined and remained low for the rest of the season in Rietondale. From September to December for all three years of the study, the population levels Of DBM were high, reaching a maximum of 9.6larvae per plant in September 1997, and remained low from January to August in Bapsfontein. The number of adult moths per trap per week ranged from 0 to 91 in Rietondale, peaking in January 1996 and September 1997. There was no correlation between infestation levels and the pheromone trap catches. In contrast to Rietondale, there was a high correlation between pheromone trap catches and subsequent larval infestations at Bapsfontein. Although DBM infestation levels were generally low, parasitism levels often reached 100% caused by a complex of parasitoids. During the period of study, the following hymenopteran parasitoids were recorded: Cotesia plutellae (Kurdjumov) and Apanteles eriophyes (Nixon), Braconidae), both larval parasitoids, Diadegma mollipla (Holmgren) (Ichneumonidae), and Oomyzus sokolowskii (Kurdjumov) (Eulophidae), larval-pupal parasitoids, Diadromus collaris (Gravenhorst) (Ichneumonidae) pupal parasitoid, and the hyperparasitoids Mesochorus sp. (Ichneumonidae) and Pteromalus sp. (Pteromalidae). Cotesia plutellae was the most abundant parasitoid occurring throughout the year..
- Full Text:
- Date Issued: 2002
Distributed control applications using local area networks: a LAN based power control system at Rhodes University
- Authors: Sullivan, Anthony John
- Date: 2002
- Subjects: Embedded computer systems , Local area networks (Computer networks) , Linux
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5461 , http://hdl.handle.net/10962/d1005246 , Embedded computer systems , Local area networks (Computer networks) , Linux
- Description: This thesis describes the design and development of both the hardware and software of an embedded, distributed control system using a LAN infrastructure for communication between nodes. The primary application of this system is for power monitoring and control at Rhodes University. Both the hardware and software have been developed to provide a modular and scalable system capable of growing and adapting to meet the changing demands placed on it. The software includes a custom written Internet Protocol stack for use in the embedded environment, with a small code footprint and low processing overheads. There is also Linux-based control software, which includes a web-based device management interface and graphical output. Problems specific to the application are discussed as well as their solutions, with particular attention to the constraints of an embedded system.
- Full Text:
- Date Issued: 2002
- Authors: Sullivan, Anthony John
- Date: 2002
- Subjects: Embedded computer systems , Local area networks (Computer networks) , Linux
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5461 , http://hdl.handle.net/10962/d1005246 , Embedded computer systems , Local area networks (Computer networks) , Linux
- Description: This thesis describes the design and development of both the hardware and software of an embedded, distributed control system using a LAN infrastructure for communication between nodes. The primary application of this system is for power monitoring and control at Rhodes University. Both the hardware and software have been developed to provide a modular and scalable system capable of growing and adapting to meet the changing demands placed on it. The software includes a custom written Internet Protocol stack for use in the embedded environment, with a small code footprint and low processing overheads. There is also Linux-based control software, which includes a web-based device management interface and graphical output. Problems specific to the application are discussed as well as their solutions, with particular attention to the constraints of an embedded system.
- Full Text:
- Date Issued: 2002
Dublin founders of ringing bells
- Authors: Lewis, Colin A
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6174 , http://hdl.handle.net/10962/d1012366 , http://www.ringingworld.co.uk
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa. , The refurbishment and rehanging in a new frame in 1989 of the eight bells of St Patrick's Cathedral in Melbourne, Australia, was an indirect compliment to the quality of Irish workmanship. The bells, with a tenor of 13½ cwt, were cast in Dublin by Murphy's Bell Foundry to the order of Bishop Goold. They arrived in Melbourne in 1853. The bells were intended for St Francis' Church in Elizabeth Street, Melbourne, which had no tower! Eventually, in 1868, they were hung in the south tower of the cathedral. During the nineteenth and twentieth centuries there were at least four founders in Dublin who cast ringing bells: John Murphy, James Sheridan, Thomas Hodges and Matthew O'Byrne.
- Full Text:
- Date Issued: 2002
- Authors: Lewis, Colin A
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6174 , http://hdl.handle.net/10962/d1012366 , http://www.ringingworld.co.uk
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa. , The refurbishment and rehanging in a new frame in 1989 of the eight bells of St Patrick's Cathedral in Melbourne, Australia, was an indirect compliment to the quality of Irish workmanship. The bells, with a tenor of 13½ cwt, were cast in Dublin by Murphy's Bell Foundry to the order of Bishop Goold. They arrived in Melbourne in 1853. The bells were intended for St Francis' Church in Elizabeth Street, Melbourne, which had no tower! Eventually, in 1868, they were hung in the south tower of the cathedral. During the nineteenth and twentieth centuries there were at least four founders in Dublin who cast ringing bells: John Murphy, James Sheridan, Thomas Hodges and Matthew O'Byrne.
- Full Text:
- Date Issued: 2002
Dynamics of early stage fishes associated with selected warm temperate estuaries in South Africa
- Authors: Strydom, Nadine Amelia
- Date: 2002
- Subjects: Estuarine fishes -- South Africa Fishes -- Infancy -- South Africa Estuarine ecology -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5262 , http://hdl.handle.net/10962/d1005106
- Description: Early stage fishes, namely larvae and early juveniles, were collected from 12 estuaries and associated habitats in the warm temperate region of South Africa between July 1998 and December 2000. This study served to provide new information and expand on existing knowledge of early stage fish assemblages associated with various types of Eastern Cape estuaries. A total of 65 536 predominantly postflexion fish larvae were collected. Together with early juveniles, taxa comprised 72 species from 25 teleost fish families. Surf zones associated with two intermittently open estuaries showed that estuary-dependent marine species predominated in this zone. Early stage fishes responded positively during natural estuary opening events and concentrated along the estuary outflow plume, suggesting that cueing from estuary and/or river water may be taking place. A habitat study in the Swartkops Estuary, using light traps, showed that newly recruited larval fishes concentrated along the margins of the estuary and unlike their older juvenile counterparts, were poorly represented in eelgrass beds. A multi-estuary comparison, including seven permanently open and five intermittently open estuaries, indicated that early stage fish assemblages were more diverse than indicated by past investigations. Early stage fishes were also shown to concentrate in the mesohaline regions of these estuaries. Studies of estuaries with altered freshwater flow regimes were also included in the research. A regulated release of dam water in the euhaline Kromme Estuary failed to induce a cueing response from estuary-dependent marine fish larvae. This project showed that large amounts of freshwater are required to reverse the negative effects of river impoundments. The release study did show that estuary-resident fishes were sensitive to small natural pulses of freshwater and responded by spawning. However, excessive river supply through an inter-basin water transfer scheme was shown to have a flushing effect on the larvae and early juveniles of the estuary-resident Gilchristella aestuaria in the upper reaches of the Great Fish Estuary. This effect was evident in comparisons with the freshwater starved Kariega Estuary where concentrations of G. aestuaria, a species usually more abundant in freshwater rich estuaries, were considerably higher. This finding suggests that freshwater minima and maxima be considered when assessing and managing estuarine systems.
- Full Text:
- Date Issued: 2002
- Authors: Strydom, Nadine Amelia
- Date: 2002
- Subjects: Estuarine fishes -- South Africa Fishes -- Infancy -- South Africa Estuarine ecology -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5262 , http://hdl.handle.net/10962/d1005106
- Description: Early stage fishes, namely larvae and early juveniles, were collected from 12 estuaries and associated habitats in the warm temperate region of South Africa between July 1998 and December 2000. This study served to provide new information and expand on existing knowledge of early stage fish assemblages associated with various types of Eastern Cape estuaries. A total of 65 536 predominantly postflexion fish larvae were collected. Together with early juveniles, taxa comprised 72 species from 25 teleost fish families. Surf zones associated with two intermittently open estuaries showed that estuary-dependent marine species predominated in this zone. Early stage fishes responded positively during natural estuary opening events and concentrated along the estuary outflow plume, suggesting that cueing from estuary and/or river water may be taking place. A habitat study in the Swartkops Estuary, using light traps, showed that newly recruited larval fishes concentrated along the margins of the estuary and unlike their older juvenile counterparts, were poorly represented in eelgrass beds. A multi-estuary comparison, including seven permanently open and five intermittently open estuaries, indicated that early stage fish assemblages were more diverse than indicated by past investigations. Early stage fishes were also shown to concentrate in the mesohaline regions of these estuaries. Studies of estuaries with altered freshwater flow regimes were also included in the research. A regulated release of dam water in the euhaline Kromme Estuary failed to induce a cueing response from estuary-dependent marine fish larvae. This project showed that large amounts of freshwater are required to reverse the negative effects of river impoundments. The release study did show that estuary-resident fishes were sensitive to small natural pulses of freshwater and responded by spawning. However, excessive river supply through an inter-basin water transfer scheme was shown to have a flushing effect on the larvae and early juveniles of the estuary-resident Gilchristella aestuaria in the upper reaches of the Great Fish Estuary. This effect was evident in comparisons with the freshwater starved Kariega Estuary where concentrations of G. aestuaria, a species usually more abundant in freshwater rich estuaries, were considerably higher. This finding suggests that freshwater minima and maxima be considered when assessing and managing estuarine systems.
- Full Text:
- Date Issued: 2002
Economic impact of international labour migration on Lesotho's development, 1986-1998: towards an international labour migration policy for the Southern African region
- Authors: Maro, Mkasafari Grace
- Date: 2002
- Subjects: Migrant labor -- South Africa , Migrant labor -- Lesotho , Foreign workers -- South Africa , Miners -- South Africa , Miners -- Labor unions -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1058 , http://hdl.handle.net/10962/d1007496 , Migrant labor -- South Africa , Migrant labor -- Lesotho , Foreign workers -- South Africa , Miners -- South Africa , Miners -- Labor unions -- South Africa
- Description: The aim of the thesis is to identify the pressures that contributed to the rise in international labour migration in Lesotho, and to investigate how these pressures are impacting upon the modernization process in the country, particularly at a time when employment opportunities are scarce in the southern African region. International labour migration has been used as a development tool throughout history, but especially in the 20th century by developing countries with dual labour markets. Newly independent developing countries with dual labour markets adapted the strategy of import substitution industrialization (lSI), with an emphasis on protecting infant industries and promoting pro-labour policies. In the post-colonial period the international demand for lowskilled workers rose, particularly in the North (developed countries), and in mineral rich countries including the oil exporters and South Africa, and the newly industrialising countries in East Asia. International labour migration to these countries was adapted as an integral development tool by the governments of the lSI countries. Most migrants were low-skilled and temporary workers in the destination countries. Although no multilateral institutional framework existed, usually both the sending and receiving countries adapted unilateral and bilateral migration policies to guarantee the gains from migration. Workers were thus "protected" to varying degrees under such agreements. From the 1970s, the North experienced a slowdown in the growth in demand for unskilled workers. In the 1980s, many lSI countries experienced devastating economic crises that forced them to abandon the lSI policy and adapt the export-led industrialisation (EOI) policy with an emphasis on trade liberalization. The switch from lSI to EOI in developing countries with dual labour markets led to the downsizing of public sector employment, the removal of marketing boards formally used by small-scale agricultural farmers, and the expansion of export processing zones (EPZs). These outcomes resulted in a rise in push internal migration, and international migration from these countries especially to other developing countries. At the same time, since the late 1980s, capital has acquired greatly enhanced mobility at the global level. The adaptation of EOI and the full mobility of capital at the global level altered the institutional structure within which labour migration was governed both nationally, and internationally. At the national level stricter unilateral policies were reinforced by receiving countries for low-skilled labour, while less strict policies applied for skilled labour. These remain in operation in conjunction with the earlier bilateral agreements. At the international level, there remains a lack of policy to regulate international labour migration. Under the current enhanced mobility of capital, international migrants are thus left vulnerable. Lesotho fits this pattern. Faced with a dual economy and an abundance of semi-skilled labour, Lesotho has been a principal supplier of labour to the South Africa's mining industry since its independence. Lesotho's industrial diversification thus mirrors South Africa's industrial diversification. In the lSI phase (1968 - 1987), international labour migration became the most important tool of economic welfare generation in Lesotho. Bilateral agreements were signed in the early 1970s between Lesotho and South Africa to guarantee the gains from migration. Since the late I980s, the mining industry in South Africa began to downsize production and employment. Fewer novice miners from Lesotho were recruited to work in South Africa. The adaptation of the EOI policy in Lesotho in 1987 introduced EPZ industrialization and trade liberalization. Nevertheless, the retrenchment of mine workers from South Africa is occurring at a time when Lesotho is experiencing an employment crisis. The political independence of South Africa in 1994 was accompanied by stricter international migration policies by the new democratic government of South Africa. Most migrant workers in South Africa are thus now faced with a two-door policy (of the earlier bilateral agreements and the amendments to the Aliens Control Act). This system has left migrant workers vulnerable to exploitation by both employers and the law (police) in South Africa. Nevertheless, international migration from Lesotho to South Africa continues to expand, particularly of the new type of migration - semiskilled female workers in the services sector. At the same time, South Africa is also experiencing an employment crisis. The most important policy implications are, firstly, that migration is subject to the same "casualisation" as other work, with the effects made worse by the "statelessness" of migrants, who are most vulnerable to exploitation. Secondly, multilateralism is needed (e.g., SADC) and holistic, multilateral policies are required. It is clear that under the new global division of labour ad hoc policy towards international labour migration is ineffective.
- Full Text:
- Date Issued: 2002
- Authors: Maro, Mkasafari Grace
- Date: 2002
- Subjects: Migrant labor -- South Africa , Migrant labor -- Lesotho , Foreign workers -- South Africa , Miners -- South Africa , Miners -- Labor unions -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1058 , http://hdl.handle.net/10962/d1007496 , Migrant labor -- South Africa , Migrant labor -- Lesotho , Foreign workers -- South Africa , Miners -- South Africa , Miners -- Labor unions -- South Africa
- Description: The aim of the thesis is to identify the pressures that contributed to the rise in international labour migration in Lesotho, and to investigate how these pressures are impacting upon the modernization process in the country, particularly at a time when employment opportunities are scarce in the southern African region. International labour migration has been used as a development tool throughout history, but especially in the 20th century by developing countries with dual labour markets. Newly independent developing countries with dual labour markets adapted the strategy of import substitution industrialization (lSI), with an emphasis on protecting infant industries and promoting pro-labour policies. In the post-colonial period the international demand for lowskilled workers rose, particularly in the North (developed countries), and in mineral rich countries including the oil exporters and South Africa, and the newly industrialising countries in East Asia. International labour migration to these countries was adapted as an integral development tool by the governments of the lSI countries. Most migrants were low-skilled and temporary workers in the destination countries. Although no multilateral institutional framework existed, usually both the sending and receiving countries adapted unilateral and bilateral migration policies to guarantee the gains from migration. Workers were thus "protected" to varying degrees under such agreements. From the 1970s, the North experienced a slowdown in the growth in demand for unskilled workers. In the 1980s, many lSI countries experienced devastating economic crises that forced them to abandon the lSI policy and adapt the export-led industrialisation (EOI) policy with an emphasis on trade liberalization. The switch from lSI to EOI in developing countries with dual labour markets led to the downsizing of public sector employment, the removal of marketing boards formally used by small-scale agricultural farmers, and the expansion of export processing zones (EPZs). These outcomes resulted in a rise in push internal migration, and international migration from these countries especially to other developing countries. At the same time, since the late 1980s, capital has acquired greatly enhanced mobility at the global level. The adaptation of EOI and the full mobility of capital at the global level altered the institutional structure within which labour migration was governed both nationally, and internationally. At the national level stricter unilateral policies were reinforced by receiving countries for low-skilled labour, while less strict policies applied for skilled labour. These remain in operation in conjunction with the earlier bilateral agreements. At the international level, there remains a lack of policy to regulate international labour migration. Under the current enhanced mobility of capital, international migrants are thus left vulnerable. Lesotho fits this pattern. Faced with a dual economy and an abundance of semi-skilled labour, Lesotho has been a principal supplier of labour to the South Africa's mining industry since its independence. Lesotho's industrial diversification thus mirrors South Africa's industrial diversification. In the lSI phase (1968 - 1987), international labour migration became the most important tool of economic welfare generation in Lesotho. Bilateral agreements were signed in the early 1970s between Lesotho and South Africa to guarantee the gains from migration. Since the late I980s, the mining industry in South Africa began to downsize production and employment. Fewer novice miners from Lesotho were recruited to work in South Africa. The adaptation of the EOI policy in Lesotho in 1987 introduced EPZ industrialization and trade liberalization. Nevertheless, the retrenchment of mine workers from South Africa is occurring at a time when Lesotho is experiencing an employment crisis. The political independence of South Africa in 1994 was accompanied by stricter international migration policies by the new democratic government of South Africa. Most migrant workers in South Africa are thus now faced with a two-door policy (of the earlier bilateral agreements and the amendments to the Aliens Control Act). This system has left migrant workers vulnerable to exploitation by both employers and the law (police) in South Africa. Nevertheless, international migration from Lesotho to South Africa continues to expand, particularly of the new type of migration - semiskilled female workers in the services sector. At the same time, South Africa is also experiencing an employment crisis. The most important policy implications are, firstly, that migration is subject to the same "casualisation" as other work, with the effects made worse by the "statelessness" of migrants, who are most vulnerable to exploitation. Secondly, multilateralism is needed (e.g., SADC) and holistic, multilateral policies are required. It is clear that under the new global division of labour ad hoc policy towards international labour migration is ineffective.
- Full Text:
- Date Issued: 2002